Deterioration of visceral perfusion caused by intra-abdominal hypertensionin pigs ventilated with positive end-expiratory pressure

Experimental studies and clinical experience suggest that the combination o f positive end-expiratory pressure (PEEP) ventilation and intra-abdominal h ypertension might alter splanchnic hemodynamics to a significantly greater degree than the effect of either of them alone. Therefore, we assessed the intestinal and hepatic hemodynamics in two steps of PEEP ventilation, addin g tense pneumoperitoneum in a pig model. The hepatic artery, portal vein, a nd superior mesenteric artery blood flow, as well as the hepatic and intest inal mucosal microcirculation, and the hepatic pO(2) and intestinal mucosal pH, were assessed before, then with 5 cmH(2)O and 10 cmH(2)O PEEP alone, a nd in combination with a 12-mmHg pneumoperitoneum, in ten domestic pigs. St atistical analysis of the hepatic and intestinal measurements revealed a si gnificant decrease (P = 0.001) in all parameters in relation to the baselin e, during the 5-cmH(2)O and 10-mmH(2)O PEEP ventilation period. The additio n of 12 mmHg intra-abdominal pressure led to an extreme deterioration in al l parameters (P = 0.001), in relation to both the baseline and the 10-cmH(2 )O PEEP measurement. These findings demonstrate that PEEP and intra-abdomin al hypertension act cumulatively on the abdominal viscera, producing condit ions of extremely low hypoperfusion and ischemia.